Vehicle actuated progressive traffic signal



Sept. 7, 1937. c. w. NEILL 2,092,423

VEHICHE ACTUATED PROGRESSIVE TRAFFIC SIGNAL Filed Sept. 15, 1930 J1 v 30 30 17 a 8 6 3; 38

, 7 4aj27l 8 5i, 7 v #3837 W 4 9 v INVENTOR.

ATTORNEYS! Patented Sept. 7, 1937 UNiTED STATES VEHICLE ACTUATED PRQGRESSIVE TRAF- FIC SIGNAL Application September 15, 1930, Serial No. 481,878

4 Claims.

This invention relates to traffic signals and particularly to traffic signal systems in which a plurality of the signal devices are vehicle actuated.

5 It is well recognized that in traffic signal systems in which the right of way indications are shifted by arbitrary timing devices, much time is lost as the result of signal changes in favor of streets on which no traffic is moving at the time. The vehicle actuated traffic signal is a development which saves much time and greatly increases the efficiency of the isolated intersection which is controlled by traffic signals. When vehicle actuated signals are used at successive intersections along a highway, much of their efficiency is lost and the operation is no more efficient than in the case of traffic officers. It is well known that in driving along a street where the traffic at each intersection is directed by an ofilcer, it is often necessary for a vehicle to stop at most, and sometimes at all, intersections.

The principal object of this invention is to provide a trafiic signal system in whichtrafiic n may move along a highway and obtain a go signal at each intersection, and to provide vehicle actuated means for controllingthe operations of the signals so as to obtain theincreased efficiency produced by having the signals vehicle operated. A further object of the invention is to provide a at the intersectionsalong a highway and to provide operating mechanism for the signal devices which will normally display a go signal indication to traffic on the cross street but which will be operated by vehicle actuated means, to give go signal indications to a vehicle, or a platoon of vehicles, moving progressively along the highway.

Other objects and advantages of the invention will appear and will be pointed out as the description proceeds.

The invention consists in the novel features and in the combinations and constructions herein- 1 H after set forth and claimed. In describing this invention reference is had to the accompanying drawing in which like characters designate corresponding parts in all the views.

Figure 1 is a diagrammatic plan View of a highway, intersected by'a plurality of crossstreets, showing the timing devices for rendering the vehicle actuated control means operative.

Figure 2 is a wiring diagram of the mechanism intersections shown in Figure 1.

I; plurality of signal devices for directing tr-aiiic for operating the signal devices at the respective T OFFICE Progressive control of signals Figure 1 shows a highway intersected by a plurality of cross streets and signal devices I I, I 2, I55 and M are shown located at the respective intersections. These signal devices are of conventional construction and are therefore shown diagrammatically in Figure 1. The right of way indications displayed by the signal devices will normally indicate go to traffic on the cross streets and stop to traffic on the highway.

The signal devicesare shown in this position in Figure 1 in which G designates a go signal indication and S designates a stop signal indication.

As long as there is no traffic moving on the highway, the trafiic on the intersecting streets may'cross without interference from the signal devices.

Vehicle actuated means are provided for shifting the signals to indicate go to traffic on the highway and stop to trafiic on the cross streets. actuated means The vehicle include shifting mechanism,

which will be described in detail hereinafter, and vehicle actuated detector means for controlling the operation of the shiftingmechanism. This detector mechanism may be of any suitable type such as the treadle devices shown in Patent No.

1,194,668 to Schatz'le et al., August Patent No. 1,665,560 to Nelson, April 10, 1928, or

may be of the magnetic type.

Two detectors 26 and 2| are provided to control the shifting of the signal device H. The detector 20 is located on the right side of the street for vehicles moving along the highway toward the right in Figure 1. The detector 2 I. is located on the right side of the highway for vehicles moving along the highway toward the left in Figure 1.

The

operation of signal device l3. A

detector 26 operates to control the signal device I l and a second detector will be located on the other side of the signal device [4, outside the drawing.

The detailed construction of the unimportant but they are of the type operated closes an electric circuit.

field of the detectors is which when F It is necessary, therefore, to supply electric power to these detectors and if the supply of electric power is trol the shifting of the signal devices.

out off, the detectors become inoperative to con- The signal O to the highway traffic.

system shown in Figure l is designed to be operated progressively by dividing the traflic on the highway into platoons and giving a go signal at the respective intersections progressively so that a. platoon after passing the first intersection may move continuously at a predetermined rate of speed and always receive a go signal indication at each succeeding intersection. This manner of directing traffic to obtain continuous movement is Well understood by those skilled in the art. If the signaldevice displays a stop signal indication to traffic on the highway for a period of time, a platoon will form on the highway. If the signal device H is then shifted to give a go signal indication, a platoon may move to the right toward the signal device l2. If the first car of this platoon crosses the detector 22 and causes the signal device l2 to shift to give a go signal indication to the highway traffic, the platoon may move along the intersection controlled by the signal device |2 without stopping. If the detector 24, in response to actuation by the first vehicle of the platoon, shifts the signal device I3 to indicate go to highway trafiic, the platoon may continue to move without stopping. In such platoon movement of traflic however, it is necessary that some space be maintained between platoons to permit traffic on the cross streets to pass across the intersections. It is necessary, therefore, that the detectors 23, 2|, 22, 23, 24, 25 and 26 be rendered inoperative to cause the signal indications to shift if a vehicle approaches on the highway between the periods during which a platoon is due to cross the intersection. The detectors are rendered inoperative to control the shifting of the signal indications by periodically cutting off the supply of electric power to the detectors.

Electric power is furnished to the detector 20 through a conductor 30 which connects with a brush 3|. The brush 3| runs on a commutator 33 which is driven by a continuously rotating syn-- chronous motor 35. The commutator 33 is provided with a hot segment 31 and an insulating segment 38. When the brush 3| is in contact with the hot segment 3! the conductor 30 supplies electric power to the detector 2|! and if a vehicle actuates the detector 20 the signal device II will be shifted to give a go signal indication When the brush 3| is in contact with the insulating segment 38, the supply of power to the detector 20 is cut off and the detector 20 is inoperative to control the shifting of the signal device II. Thus vehicles approaching the detector 2|? and signal device during the period that the brush 3| is in contact with the insulating segment 38 will have to wait until the hot segment 3'! moves into contact with the brush 3|. It is during this time that an accumulation of traific forms on the highway and when the hot segment 3'! comes in contact with the brush 3| and the detector 29 operates the shifting mechanism to cause the signal device H to indicate go to the highway, a platoon of traffic whose length is determined to a large extent by the time of display of the said go signal, will cross the intersection controlled by the signal device H and begin its progressive movement along the highway.

The supply of power to the detector 22 is controlled by a commutator 43 which is of identical construction with the commutator 33 and is provided with a hot segment 31 and an insulating segment 38. The commutator 43 is operated by a continuously rotating synchronous motor 45 and the synchronous motors 35 and 45 are run from the same power line so that the commutators 33 and 43 rotate at exactly the same rate of speed. If the commutators 33 and rotate in a counter-clockwise direction, the hot segment 31 of the commutator '13 will be spaced in a clockwise direction from the hot segment 31 of the commutator 33. By having the hot segment 3'! of the commutators 33 and 43 so set with respect to one another, the hot segment 3? of the commutator 43 will come in contact with the brush 3| to furnish power to the detector 22, some time after the hot segment 3i oi the commutator 33 has come in contact with the brush 3| to supply power to the detector 23. Thus the detector 22 becomes operative to control shifting of the signal device l2 some time after the detector 23 becomes operative to control shifting of the signal device It. The length of this time may be adjusted by changing the setting of the hot contact segment 37 of the commutaters 33 and 43 with respect to one another. Obviously, the commutators will be set to obtain a greater lapse of time if the distance between the signal devices H and i2 is longer than if this distance is comparatively short. If the speed of progression of the trafiic platoons is to be slow, the commutators 33 and 43 will be set so as to obtain considerable lag after power is furnished to the detector 20 before it is furnished to the detector 2'2. If the traffic moves at a high speed oi progression, the time lag between the power supply to the detectors 2G and 22 may be very short.

A commutator 48 driven by a synchronous motor 49 furnishes power to the detector 23 in exactly the same manner as described in connection with detectors 20 and 22. The commutator 48 will be so set with respect to the commutator 43 that the supply of power to detector 24 will occur some time after the supply 03. power to the detector 22 and the length of this time may be adjusted to suit the distance between intersections or the speed of progression. The detector 23 re ceives its power supply from a commutator which is continuously rotated by a synchronous motor 55. From the above description it will be apparent that the commutators 43, 48 and 53 may be set in any desired relation to one another so as to obtain uniform speed of progression regardless of the distance between intersections. to obtain progression at a non-uniform rate, or to obtain a supply of power to their respective detectors in any desired sequence.

If the highway shown in Figure 1 were a oneway street, the detectors 23, 22, 24 and 26 would be sufficient to shift the signal devices. If the highway is to operate with two-way traflic, the detectors 2 I, 23 and 25 become necessary. These detectors 2|, 23 and 25 are supplied with electric power by commutators 51, 58 and 59, respectively, which are operated by synchronous motors 62?, 6| and 62, respectively. The commutator 33 furnishes power to a detector on the other side of the signal device l4 outside of the field of the drawing. The operation of the commutators 57, 58, 59 and 63 is identical with the operation of the commutators 33, 43, 48 and 53 except that the commutators 52', 58, 59 and 33 will be set so as to obtain a time lag for trafhc moving in the opposite direction. That is, the commutator 58 will be set with respect to the commutator 59 so that the supply of power to the detector 25 will occur before the supply of power to the detector 23. This difference in setting is obviously necessary due to the fact that the detectors 2|, 23

and 25 control the signal devices for platoons progressing from right to left along the highway in Figure 1. The Synchronous motors 6%, ti and 62 are connected with a different power line than the synchronous motors 35, 45, 19 and 55. It is immaterial, however, whether two power lines are used or 'a single power line used for all motors tho it is necessary that all the motors on one side of the street operate in synchronism and that the motors on the other side of the street operate in synchronism while the separate systems of the motors on opposite sides of the street may or may not be synchronizedv It is not necessary that an individual motor be supplied to each commutator.

Signal shifting mechanism The signal shifting mechanism is shown in Figure 2 and is controlled by a detector such as the detector 28 which contains an armature it to which power is supplied through the conductor 36. Actuation of the detector 263 by a vehicle will cause the armature "iii to drop into contact with the contact point 712. i The shifting mechanism is operated by a motor M which rotates in a clockwise direction but is normally stationary. A conductor segment it is rotated by the motor M. When the shifting mechanism is in normal position the conductor segment will occupy the position shown in Figure 2 with a brush it out of contact with the con ductor segment and a brush to in contact with one end of the conductor segment as shown. The conductor segment i5 is hot at all times and when the shifting mechanism is in its normal position, power from the conductor segment 15 will flow through the brush at, a conductor GI, armature 32, contact point 83, and conductor 85 to light the cross street go signal. A conduc- 4O tor 8t connects the conductor @5 with the highway stop signal.

When a vehicle actuates the detector 28 to drop the armature it! into contact with the con tact point 12, power is supplied from the conductor 3t], through the armature m, contact point l2, and conductor 89 to a relay 9G. The other side of the relay 98 is connected by a conductor 9| with a relay 92. The other side of the relay 92 is connected by a conductor 95 with a driving coil 96 of the motor it. Thus actuation of the detector 2t transmits power to the driving coil 96 to operate the motor 74 which rotates the conductor segment it.

The relay 90 operates an armature lilil which is normally held away from the relay by a spring M12. The upper end HM of the armature Hit is insulated from the other part of the armature and acts as a switch to make contact between the contact points M35 and Hit, the purpose of G0 which is to operate the caution signal as will be further explained hereinafter. The lower end of the armature its is connected by a conductor it to the conductor iii. A contact point H0 is provided to make the relay 9t stick.

When current is supplied to the relay 99,

as above described, the armature IM will be drawn into contact with the contact point IIU.

Power will be supplied to the relay 92 at the same time and the armature 82 will be drawn into contact with a contact point M2. The movement of the armature led into contact with the contact point i it] will establish a circuit from the conductor segment it through the brush 8B, conductors 8i and N28, armature IElEI, contact point H0, relay 9t, conductor ill, relay 92, and conductor 95, to the driving coil 96 of the motor. Since the relay is a stick relay, this circuit will continue as long as the brush to is in contact with the conductor segment it.

The armature 82 is normally held in contact with the contact point 83 by a spring I Hi. When the armature 82 is shifted out of contact with the contact point 83 and into contact with the contact point M2, the circuit to the cross street go signal and highway stop signal is broken and a new circuit is set up to the caution signals. This circuit to the caution signals is furnished with 'power from the conductor segment '85, through the brush 8U, conductor 8i,'armature 32, contact point II2, conductor H5, armature H'i, contact point H8, and conductor I203 to the caution signals.

The caution signals will remain displayed until the motor M has rotated the conductor segment "I5 to bring the conductor segment i5 into contact with the brush I8. When the conductor segment '55 makes contact with the brush "it power will be supplied through a conductor 5222, relay I24 and a conductor Q25 which connects with the conductor 95 to furnish a parallel circuit for the supply of power to the driving coil $6 of the motor. When current flows through the relay G24! the armature it? will be moved, against the tension of a spring I21, to break'the circuit through the contact point I H3 and establish a new circuit from the armature I I? through a contact point I30 and a conductor I32 which connects with the cross street stop signal. A conductorv E33 connects the conductor I 32 with the highway go signal.

The highway go signal and cross street stop signal will remain displayed as long as the conductor segment '65 is in contact with both of the brushes it and 80. When the motor M has rotated the conductor segment 15 until the con ductor segment I5 passes out from under the brush to, the circuit through the brush 86, conductors 8| and I08, armature IN and contact point lid to the relays to and 92 will be broken.

The springs W2 and I I4 will move the armatures Ito and 82, respectively, out of contact with the contact points I it and I I2, respectively, andinto contact with the contact points Hi5, lot and S2. Althoughthe circuit through the relays 9i) and 95 to the driving coil 96 is thus broken, the motor M will continue to run since power is supplied to the driving coil 96 from the brush it and through the conductor I22, relay I24 and conductor I25. The breaking of the circuit from the armature 82 through the contact point IE2 will cut off the supply of power to the armature II 7 and the highway go signal and cross street stop signal will no longer be displayed.

The contact point I05 is connected by a con ductor I35 with the brush I8 and when the spring I02 restores the armature Hill to normal position, power from the conductor segment 15 will be supplied through the brush I8, conductor I35, contact point I 05, end portion I 04 of the commutator I98, contact point I06, and conductor I36 to the caution signals.

When the motor M has rotated the conductor segment I5 through a complete revolution so that it returns to its normal position, as shown in Figure 2, the contact between the conductor segment l5 and the brush 78 will be broken and the supply of power through the conductor I35 to the caution signals will be cut off. Also the supply of power to the relay I24 and motor coil 96 will be out 01f. The spring I21 will therefore restore the armature I I! to its normal position in contact with the contact point H8, and the motor 14 will stop since no circuits are closed which will supply power to the driving coil 96.

The conductor segment I5 will make contact with the brush 80 just before the shifting mechanism reaches normal position and the supply of power from the brush 80 to the cross street go signal and highway stop signal will be restored.

Time extension Means are provided to extend the time of the highway go signal to permit long platoons to cross before the signals return to normal position. The time extension means include a conductor I40 which connects the contact point 12 with a bucking coil I42 which is associated with the motor I4. As long as the armature I is held in contact with the contact point I2 power will be supplied from the armature 10, through the contact point I2, and conductor I40 to the bucking coil I 42 which is arranged to counteract to a large extent, the effect of the driving coil 96 and thus causing the motor I4 to operate at a greatly reduced rate of speed. The greater the number of vehicles which actuate the detector "I0 during a highway go period, the greater will be the bucking effect of the coil I42 and the time required for the conductor I to make a complete rotation will thus be increased to accommodate the length of the platoon. The bucking coil I42 may be of sufficient strength to entirely stop the motor I4 and preferably the amount of current flowing through the bucking coil I 42, and the consequent retarding effect of this coil, is adjusted by means of an adjustment resistance I44 which is inserted between the conductor I and the bucking coil I42.

From the foregoing description it will be apparent that I have devised a particularly efficient signal system for directing street traffic. This system is illustrated in its preferred embodiment but changes and modifications may be made without departing from the spirit of the invention as set forth in the appended claims.

What I claim is:

1. In a street trafiic signal system for a highway intersected by a plurality of cross streets, signal devices for the respective intersections and normally indicating right of way to trafiic on the cross streets; mechanism for shifting the right of way indication to the highway, including vehicle actuated means in the highway associated with each of the shifting devices, for controlling the shiftingof the right of way indication to the highway; a timer associated with each vehicle actuated means for periodically rendering said vehicle actuated means effective, each of said timers being operable in a predetermined timed relationship with the timers at adjacent intersections, whereby the vehicle actuated means are rendered effective upon actuation by vehicular traffic to shift the signal indications progressively down the highway.

2. In a street trafiic signaling system for a highway intersected by a plurality of cross streets, signal devices at the respective intersections normally indicating right of way to the cross streets and stop to the highway, means associated with the signal device at each intersection and operable, upon actuation by a vehicle on the highway, to shift the right of way indication to the highway and stop to the cross street, and means for periodically rendering said actuation of each shifting means effective only in a related predetermined sequence.

3. In a street traffic signaling system for a highway intersected by a plurality of cross streets, signal devices at the respective intersections normally indicating right of. way to the cross streets and stop to the highway, a traflic actuatable controller associated with each signaling device and operable, upon actuation by a vehicle on the highway, to shift the right of way indication to the highway, and stop indication to the cross street, and means for rendering the actuation of each controller effective to cause said shift of right of way indication at each succeeding intersection only in a related predetermined sequence.

4. In a street trafiic signaling system for a highway intersected by a plurality of cross streets, signal devices at the respective intersections normally indicating right of way to the cross streets and stop to the highway, 2. traffic actuatable controller associated with each signaling device and operable, upon actuating by a vehicle on the highway, to shift the right of way indication to the highway, and stop indication to the cross street, and to maintain said signal devices in such shifted condition for a predetermined length of time and subsequently return said signal devices to normal indication, and means for rendering the actuation of each controller eifective to cause said shift of right of way indication at each succeeding intersection only in a related predetermined sequence.

CHARLES W. NEILL. 

